The present invention relates to a new and improved apparatus for the conjoint gripping or seizing of bobbins on a textile machine, especially a ring-spinning or ring-twisting machine.
In its more specific aspects, the apparatus for the common gripping of empty or wound bobbins on a ring-spinning or ring-twisting machine, is of the type comprising pin members or spigots which are insertable into the bobbins, are formed of a rigid material, and are mounted on a support or carrier extending along the textile machine. Further, there is provided a hose or tube member which extends along the support, the internal pressure of the hose member being variable. The hose member extends in the lengthwise direction of the support between an abutment and the pin members and serves the purpose, when subjected to an increased internal pressure, of pressing the bobbins against the pin members inserted therein.
From the German Pat. No. 1,282,526 and the German Patent Publication Nos. 1,710,054 and 2,220,861 it is already known in this art to insert respective grippers into the interior of each of the bobbins for the conjoint gripping or seizing of the bobbins or the bobbins together with the thread packages wound thereon. Thereafter, these grippers are expanded by means of a pressurized fluid medium, with the result that the bobbins are retained by these grippers.
The gripping of the bobbins in the aforedescribed manner is associated with a number of drawbacks. For instance, if there is present an inexact positioning of the bobbins it can happen that during insertion of the grippers into the bobbins a gripper will graze or strike the bobbin at its upper edge. Since the wall of the gripper is formed of an elastic or flexible material there exists a certain danger that it will be damaged. Equally, it also repeatedly happens that during the conjoint gripping action a bobbin is missing at certain positions for various operational reasons. Since all of the grippers are connected to the same pressurized fluid medium and are conjointly expanded, there prevails the danger that the grippers which do not find any bobbins into which they can enter will over expand so that they experience a permanent deformation or even tend to burst.
These drawbacks can be avoided with an apparatus of the initially mentioned type which can be constructed, for instance, in accordance with the teachings of the German Pat. No. 2,062,535. In contrast to the use of grippers which expand when pressurized, here the hose or tube member always experiences approximately the same conditions, irrespective of whether or not there is present a bobbin. Even if there is not present a bobbin the pin member, which is present at the site of the missing bobbin, counteracts an overexpansion of the hose member. Damage to the pin members during their immersion into the bobbins is avoided because these pin members are formed of a rigid or solid material.
A feature of the apparatus disclosed in the aforementioned German Pat. No. 2,062,535 is that the bobbins clamped between the circular-cylindrical shaped grippers or pin members and the hose member or tube are retained with great accuracy as concerns swinging movements occurring about the pin members in a direction normal to the longitudinal direction of the support or carrier. However, the positioning of the bobbins with regard to swinging movements of the bobbins parallel to the longitudinal direction of the support is not fixed with the necessary precision.